The use of a single flanged and shanked seal ring in a pipe fitting was already disclosed in the first patent application which had been filed by me on 20th May, 1974 and received the No. 51117 A/74. The use of a two seal ring unit for a pipe fitting relates to the application for patent of addition being also filed by me on 18th Apr., 1975, which received the No. 49191 A/75.
According to the first Italian patent application, the invention relates to a new flanged and shanked seal ring to be employed in a pipe fitting, the shank of which is slightly tapered in order to make easier its insertion into the pipe end of a pipe to be joined through said pipe fitting. Also because of its suitable small thickness, the shank outer shape is deformable, so that a perfect accommodation thereof will be obtained within that pipe end, while a contemporary flaring of the pipe end edge is due to the properly flanged head of this new seal ring which is acting thereon. A fluid flow tightness is thereby realized therebetween.
Employment of a pipe fitting is essential in many applications, e.g. for sanitary service installations or for pipes in pneumatic or hydraulic systems, etc., and the application may concern the joining of coaxial pipe sections, or tees, elbows, etc.
One of the more important problems relating to these pipe fittings concerns an easy and snug assembling of same between pipe sections to be joined and to reach a reliable tightness at the joining points, preferably without using any auxiliary gasket. The solution much more applied up to date concerned the employment of seal rings which are interposed between the pipe to be joined and the piece to which the joining is to be accomplished. According to the prior art, seal rings have been mounted on the outside of the pipe to be joined, the outer and inner shape of such seal ring been selected so that to form a tight joining of pipe sections as reliable as possible, also with deformation at the points where the pipe sections were joined, the tightness having evidently to be maintained when the fluid flow has the pressure in accordance with the scope of installation.
While by using such a seal ring on the outside of the pipe to be joined a sufficient tightness for fluid flow could by itself be obtained, in the practice some drawbacks have been pointed out, and a particular care was deemed as necessary by assembling the pipe fitting in order do not provide any stress or strain, even if an occasional type, at the joining points. As a consequence of these stresses or strains the pipe fitting assembly could result mechanically no good and also defective for its operative purpose. The edge of the pipe to be joined may, for example, undergo some bending stress by mounting such seal ring, and the drawback is not always evidenced by the operator during the assembling work. An undesirable deformation may only thereafter be noted and in consequence of same the pipe fitting operation will be negatively affected.
The use of a stiffening ring has further been suggested, and the application of same into the end portion of the pipe to be joined is oft performed. This solution of the problem has not yet be found, however, as a practical manner for avoiding such drawback. In any case the operator must show its best care in assembling pipe fittings of this type.
The main object of the present invention is to provide at least one flanged and shanked seal ring as integral body, which, because of the particular configuration of its flanged head and shank fulfils at the same time the function of seal ring and stiffening sleeve, because the shank of this seal ring will be inserted into the pipe end of the pipe to be joined, in order to avoid the drawback of prior art pipe fitting.
Another object of the present invention is to provide an integral flanged and shanked seal ring the shank of which is slightly tapered in order to be easily inserted into said pipe end by lightly forcing same by hand, the flanged head of said ring bein so shaped that a further light force will be necessary to further ensure the shank within said pipe end in a position which does not provide any undesirable stress or strain therein. When the assembling of such flanged and shanked seal ring is carried on, the flanged head causes the flaring of the pipe edge of the pipe to be joined, the inner surface of which will then tightly contact the corresponding lower outer surface of the flanged head.
A further object of the present invention is to provide the intermediate portion of the ring shank with an annular protuberance which is protruding from the outer surface thereof, the function of which is to make easier the flaring of the pipe edge for said tight contact with the facing lower outer surface of the flanged head, as well as a perfect accomodation of the peripheral surface of the shank within the end portion of the pipe being joined, because the suitable thin thickness of the ring tubular shank allows the necessary deformation thereof for said accomodation. As the thickness of the ring shank is suitably small, when its insertion into the end portion of the joined pipe is accomplished the outer protuberance results little by little transferred to the inner passage of the ring shank up to its complete protruding from the inner surface thereof, as an annular rib about the ring axis. The function of same will then be that of stiffening sleeve integral with the flanged head of this seal ring.
Another object of the present invention is to provide also a second, auxiliary annular ring to be mounted on the outside of the end portion of the pipe to be joined, in order to cooperate with the first flanged and shanked seal ring as above and make easier the assembling of a pipe fitting of this type, in order to avoid any possibility of eventual seizing of same when the assembling is to perform, the seizing being for example due to a not very good finish of the component members of the pipe fitting.